Method and apparatus for regulating the tension of a moving threadlike element

ABSTRACT

A thread-like element is advanced over one side of and in contact with a member which can yield in direction towards this one side. A stream of gaseous pressure fluid is directed against an opposite side of the member in direction towards the one side, and the backpressure of the fluid which develops at the one side is measured. Depending upon the pressure that has been measured, a greater or lesser retarding force is exerted on the thread-like element, this force being a function of and varying in dependence upon the measured backpressure.

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Stritzko 1 Sept. 30, 1975 [54] METHOD AND APPARATUS FOR 2,745,610 5/1956 Reyes.. 242/150 REGULATING THE TENSION OF A 2,888,216 5/1959 SimOnS, Jr. et a1. 242/149 X 2,912,185 11/1959 Vossen v. 242/150 MOVING THREADLIKE ELEMENT 3,146,969 9/1964 Lindseym. 242/150 [75] Inventor: Vilem Stritzko, Strengelbach, 3.314.619 /1 7 Kerstellel' 242/1 7 X S i l d 3,533,574 10/1970 Cooper .1 242/150 3,565,027 2/1971 Miller et a1. 242/150 X [73] Assignee: Bleiche A.G., Zofingen, Switzerland 2 Filed; May 3 974 Primary E.\'uminer-Stanley N. Gilreath Attorney, Agent, or FirmMichael S. Striker 121] Appl. No.: 475,149

1 1 ABSTRACT Foreign Application Priority Data A thread-like element is advanced over one side of June 6, 1973 Switzerland 8168/73 n in ct with a member which can yield in direction towards this one side. A stream of gaseous [52] U.S. Cl. 242/150 pr r fluid is irected against an Opposite side of 1511 Int. Cl. Bh 59/24 h member in direction towards h one side, and he [58] Field of Search 242/150, 147 R, 147 A, kpreSSu e 0f the fluid which develops at the one 242/149, 45, 75,2, 753, 153, 154 155, 156, side is measured. Depending upon the pressure that 156,2 has been measured, a greater or lesser retarding force is exerted on the thread-like element. this force being [56] References Cited a function of and varying in dependence upon the UNITED STATES PATENTS measured backpressure.

2,610,813 9/1952 Campbell 242/150 9 Claims, 5- Drawing Figures Sept. 30,1975 Sheet 1 of 2 3,908,929

US. Patent US. Patent Sept. 30,1975 Sheet 2 of2 3,908,929

METHOD AND APPARATUS FOR REGULATING THE TENSION OF A MOVING THREADLIKE ELEMENT BACKGROUND OF THE INVENTION The present invention relates generally to a method and an apparatus for regulating the tension of a moving thread-like element, such as a filament, yarn or the like. It is particularly suitable in conjunction with textile machines.

In many applications, and particularly in textile ma chines, it is important that a moving thread-like element, such as a filament, thread, a yarn, or the like, which may for instance be being wound onto a bobbin, be at all times maintained at a certain specific tension. For this purpose, it is necessary that the tension of the element be constantly measured and that a retarding force be exerted upon the element if the tension drops below the preselected level, or that a retarding force being exerted should be decreased if the tension rises above a predetermined level. Devices for this purpose are already known.

Thus, it is known to have the element traverse a stream of gaseous fluid, and to use the backpressure in the fluid which develops upstream (with respect to the flow of the fluid) of the thread-like element for controlling the operation of the device which exerts a retarding force. The control here is based upon the deflection of the thread-like element by the stream of fluid, but it is not universally applicably with equal accuracy because the amount of backpressure which develops depends upon the thickness of the thread-like element, so that the apparatus will respond differently if it is used with elements of different thicknesses.

SUMMARY OF THE INVENTION It is therefore a general object of the present invention to provide an improved method of controlling and regulating the tension of a thread-like advancing elementl Another object of the invention is to provide an improved apparatus for carrying out the method.

It is a further object of the invention to provide such an improved method and apparatus which are capable of providing a precise tension regulation for the threadlike element without in any sense being dependent upon or influenced by different thicknesses of the element.

In keeping with the above objects, and with others which will become apparent hereafter, one feature of the invention resides in a method of regulating the tension of a moving thread-like element, which, briefly stated, comprises the steps of advancing a thread-like element over one side of and in contact with a member which can yield in the direction towards this one side. A stream of gaseous pressure fluid is directed against an opposite side of the member in direction towards the one side, and the backpressure of the fluid is measured which develops at the aforementioned other side. A retarding force is exerted upon the thread-like element which is a function of and varies in dependence upon, the measured backpressure.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation,

together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly sectioned view illustrating a first embodiment of the invention;

FIG. 2 is a horizontal section of FIG. 1;

FIG. 3 is a fragmentary sectional view, illustrating a detail of FIG. 1;

FIG. 4 is a further fragmentary sectional view illustrating a detail of FIG. 3 and being taken on line IVIV thereof; and

FIG. 5 is a view analogous to a portion of FIG. 1, but illustrating a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 4 illustrate one embodiment of the invention, wherein a thread-like element 1 such as a filament, thread, yarn or the like, travels through a device 2 which measures its tension, and through a brake 3 which can retard the movement of the element 1 to a greater or lesser extent.

A comparison of FIGS. 1 and 2 shows particularly clearly that the device 2 is provided with a mounting plate 4 on which there is mounted a nozzle 5 which is connected via a conduit 7 with a (non-illustrated) source of compressed gaseous fluid, for instance compressed air. A cover plate 6 is mounted on the nozzle 5. The plate 4 carries a pair of abutments 8 which are arranged symmetrically with reference to the longitudinal axis of the nozzle 5 and which are contacted by the element 1. A pin or pivot 9 is also mounted on the plate 4, and turnably carries a hub 10 on which there is secured (or which is a front part with) a baffle ll shaped as a segment of a circle having air passage openings 12. The baffle 11 therefore can turn about the axis of the shaft 9; it is located between the outlet opening of the nozzle 5 and the advancing element 1 and extends into the stream of compressed fluid discharged by the nozzle 5.

The pressure exerted by the stream of fluid against the baffle 1 1 causes the same to be deflected about the axis of the pivot or shaft 9 and to be pressed against the element 1 which is thus deflected between the abutments 8. The fluid which passes through the opening or openings 12 acts directly upon the element 1 and tends to reduce the friction of the same with the side of the baffle 11 that faces away from the nozzle 5.

Ahead of the baffle 11, that is intermediate the same and the nozzle 5, the stream of gaseous fluid will be dammed to some extent, so that backpressure develops which is sensed by a pressure sensing device 13.

The latter includes a bore 14 formed in the plate 4, a conduit 15, and a pneumatic amplifier 16. The bore communicates with the space through which the fluid stream passes intermediate the outlet of the nozzle 5 and the baffle 11 so that the backpressure is transmitted through the bore 14 and the conduit 15 to the amplifier 16, wherein it is used for controlling the operation of the brake 3.

FIG. 2 shows more clearly that the amplifier I6 is provided with a housing 17 having a cover 18, and that an annular member 19 is located between them. The

annular member 19 engages the circumferential marginal portion of an elastic diaphragm which serves to subdivide the interior of the housing 17 into pressure chamber 21 and a vented chamber 22 communicating with the atmosphere. A pin 23 is mounted in the housing 17, axially shiftable with reference to the diaphragm l2 and extending into a diametral opening 24 in a projection 25 mounted on the housing 17. A bracket which is connected with the pin 23 is identified with reference numeral 26 and is mounted in the opening 24 for shiftable displacement. The free end of the projection 25 is formed with a tapped bore 27 into which a screw 28 can be threaded. A helical spring 29 is mounted between the bracket 26 and the screw 28 and can be tensioned or relaxed by appropriate turning of the screw 28. A pair of brake plates 30 and 31 are freely turnably mounted on the projection 25, and the moving of thread-like element 1 passes between them. The bracket 26 presses the plate 31 against the plate 30 and the latter against the housing 17 so that the two plates 30 and 31 together act to exert a retarding force upon the element 1.

FIGS. 3 and 4 show that the baffle 11 is formed on its side facing toward the nozzle 5 with a relatively sharp edge S, whereas the side facing away from the nozzle 5 is formed with a groove F through which the element 1 extends and wherein the element 1 is stabilized against lateral displacement.

When the element 1 travels in the direction of the arrow P (see FIG. 1) a stream of compressed gaseous fluid is ejected at constant speed from the nozzle 5 against the baffle 11. If the tension of the thread-like element 1 is low, then the baffle ll deflects the portion of the element 1 which is located between the abutments 8 to a significant extent, and in consequence the backpressure which develops in the region opposite the bore 14 decreases. This causes a decrease in the chamber 21, and the spring 29 pushes the pin 23 into the housing 17, causing the bracket 26 to press the back plate 31 against the brake plate 30, with the result that a retarding force is exerted upon the element 1, causing the tension thereof to increase. As the tension in creases, on the other hand, the moving element 1 causes the baffle 11 to tilt about the pivot 9 towards the nozzle 5. The closer the baffle l l approaches the opening of the bore 14, the larger will become the backpressure of gaseous fluid which develops opposite the bore 14. This causes the pressure which is communicated to the chamber 21 to increase, and thereby to deflect the diaphragm 20 against the pin 23 and to push the same out of the housing 17, counter to the effect of the spring 29, so that the retarding force exerted upon the element 1 between the plates 30 and 31 decreases. This causes the tension of the element 1 to similarly decrease, and the stream of air issuing from the nozzle 5 can now again deflect the baffle 11 in clockwise direction about the pivot 9, more strongly deflecting the element 1 between the abutments 8 and causing a repetition of the operation just described. Thus, the tension of the element 1 is constantly being adjusted and can be maintained at a preset level.

The embodiment in FIG. 5 is largely the same as that of FIGS. 1 4. Only that portion has been illustrated which differs from the corresponding portion of FIG. 1, and like reference numerals have been used to identify like components. Those portion of FIG. 1 4 which have not been shown in FIG. 5 should be understood to be present in the latter Figure also.

FIG. 5 differs from FIGS. 1 4 in that the baffle 11 is replaced by an essentially wing-shaped member 11 which is not provided with the openings 12 but is otherwise mounted in the same manner as the baffle 11 and functions in the same way.

It should be understood that in place of the members 11 and 11 it is also possible to use a member which is longitudinally shiftablc in the direction of flow of the fluid stream, intermediate the abutments 8 and being guided by appropriate guides. In this case, the deflection of the element 1 would be the result of the displacement of this member by the force of the fluid stream, counterbalanced by the tension exerted upon the element by the moving thread-like element 1.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a controlling of the tension of a movable thread-like element, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. v

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features, that from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A method of regulating the tension of a moving thread-like element, comprising the steps of advancing a thread-like element over one side of and in contact with a member which can yield in direction towards said one side; directing a stream of gaseous pressure fluid against the opposite side of said member in direction towards said one side; measuring the backpressure of said fluid which develops at said opposite side; and exerting a retarding force on said element which is a function of and varies in dependence upon, the measured backpressure.

2. An arrangement for regulating the tension of a moving thread-like element, comprising wall means defining a restricted space for passage of a moving threadlike element; nozzle means for blowing a stream of pressurized gaseous fluid into said space transversely of the path of movement of said element; a yieldable member mounted in said space intermediate said nozzle means and said path, said member contacting said element and being deflectable against the tension of the same by said stream of fluid; measuring means for measuring the backpressure resulting intermediate said member and said nozzle means from backing-up of said fluid; and braking means controlled by said measuring means and operative for braking said element with a force which is a function of and varies with the measured backpressure.

3. An arrangement as defined in claim 2, wherein said yieldable member is a baffle which is mounted for turning movement about an axis extending transverse to said path and said stream.

comprising guide portions on said side facing said element for guiding said element on the same.

8. An arrangement as defined in claim 7, wherein said guide portions comprise a groove formed in said side facing said element.

9. An arrangement as defined in claim 7, wherein said side facing said element is convex. 

1. A method of regulating the tension of a moving thread-like element, comprising the steps of advancing a thread-like element over one side of and in contact with a member which can yield in direction towards said one side; directing a stream of gaseous pressure fluid against the opposite side of said member in direction towards said one side; measuring the backpressure of said fluid which develops at said opposite side; and exerting a retarding force on said element which is a function of and varies in dependence upon, the measured backpressure.
 2. An arrangement for regulating the tension of a moving threadlike element, comprising wall means defining a restricted space for passage of a moving thread-like element; nozzle means for blowing a stream of pressurized gaseous fluid into said space transversely of the path of movement of said element; a yieldable member mounted in said space intermediate said nozzle means and said path, said member contacting said element and being deflectable against the tension of the same by said stream of fluid; measuring means for measuring the backpressure resulting intermediate said member and said nozzle means from backing-up of said fluid; and braking means controlled by said measuring means and operative for braking said element with a force which is a function of and varies with the measured backpressure.
 3. An arrangement as defined in claim 2, wherein said yieldable member is a baffle which is mounted for turning movement about an axis extending transverse to said path and said stream.
 4. An arrangement as defined in claim 3, said baffle having a concave side facing towards said nozzle means.
 5. An arrangement as defined in claim 4, said baffle having at least one fluid aperture.
 6. An arrangement as defined in claim 4, wherein said baffle is shaped as a segment of a circle.
 7. An arrangement as defined in claim 4, said baffle having another side facing said element; and further comprising guide portions on said side facing said element for guiding said element on the same.
 8. An arrangement as defined in claim 7, wherein said guide portions comprise a groove formed in said side facing said element.
 9. An arrangement as defined in claim 7, wherein said side facing said element is convex. 